Endoscopes are welt-known in the art and are flexible devices that are inserted into a natural body orifice such as the mouth or anus to provide visual and surgical access to portions of the upper and lower gastrointestinal (GI) tract. Endoscope accessible portions of the lower GI tract extend from the anus to the small intestine, and during this journey, the flexible endoscope must traverse a torturous convoluted path through the anus, the rectum, and through the large intestine to the ileocecal opening of the small intestine. The torturous path includes an “S” shaped passage through the rectosigmoid junction and the sigmoid colon, and around several larger than right angled bends of the splenic flexure and hepatic flexure. Additionally, in small bowel enteroscopy, an endoscope must traverse a large torturous convoluted path having multiple “S” shaped passages.
Before insertion of the endoscope, the patient is given drugs to purge fecal matter from the lower GI tract. Once emptied, the tubular walls of the large intestine can flatten or collapse together into a flattened tubular configuration. The collapsed intestines may inhibit passage of the flat face of the distal end of the endoscope, and the collapsed tissue can inhibit visualization by pressing against or near to a camera mounted within the flat face. To enhance the passage of the endoscope through the collapsed lower GI tract and to improve visualization, insufflation gas is routinely pumped into the patient's tower GI tract to expand and distend the collapsed tubular tissues. The expanded walls may improve visualization and reduce tissue contact with the flat face of the endoscope as it is pushed farther and farther into the insufflated lower GI tract. The distal portion of the endoscope is steerable, and the insufflated tissue can provide room for the surgeon to visually steer the endoscope through the path ahead.
The administration of insufflation gas to the lower GI tract can induce abdominal discomfort, and this has led to the common practice of anesthetizing the patient during the procedure. Additionally, insufflation gas may cause lengthening of anatomy and spontaneous perforation. Post-surgical recovery times are provided to allow the patient to purge insufflation gas and to awaken from the anesthesia. CO2 is commonly used for insufflation as it is more readily absorbed through the patient's intestinal wall to reduce the post-operative recovery time. CO2 gas control systems, CO2 tanks, and CO2 gas heaters must be purchased and maintained in order to provide CO2 as an insufflation gas.
In general, a complete colonoscopy requires the physician to advance the colonoscope into the colon, negotiate the sigmoid colon, and left and right colic flexures up to the cecum. Advancement of the endoscope is generally accomplished by manipulation of a steerable tip of the endoscope, which is controlled at the proximal end of the device by the physician, in addition to torquing and pushing the endoscope forward or pulling it backward.
Problems regularly occur, however, when negotiating the endoscope through the bends of the colon, such as at the sigmoid and left and right colic flexures. These problems arise because the colon is soft and has unpredictable fixation points to the viscera of the abdomen, and it is easily distensible. Consequently, after the steerable tip of the endoscope is deflected to enter a new region of the colon, the principal direction of the force applied by the physician urging the end of the device into the patient's colon is not in the direction of the steerable tip. Instead, the force is directed along the axis of the endoscope and towards the preceding bend(s), and causes yielding or displacement of the colon wall. This problem, also known as looping, causes the colon to take a non-native shape.
The loads imposed by the endoscope on the colon wall can have a myriad of possible effects, ranging from patient discomfort to spastic cramp-like contractions of the colon and even possible perforation or dissection of the colon. Consequently, the endoscope cannot be advanced as far as the cecum in a significant number of cases.